Dynamic Filtering in a Database System

1. A method of performing an operation on data stored in a relational database, comprising: receiving a request, pertaining to a set of objects, to perform an operation on the data in the relational database, wherein the data is related to a set of objects, each object having similar properties; receiving an input; modifying the request to include at least one restriction pertaining to which data will be accessed as a function of the input; receiving information related to access restrictions to the data of the set of objects; checking if access restrictions exist on objects pertaining to the request; executing the modified request to perform the operation if the request pertains to retrieving all of the data pertaining to at the least one object and there are no access restrictions to the data of said at least one object or if the request pertains to retrieving only a portion, but not all, of the data pertaining to said at least one object and the access restrictions do not pertain to the portion of the data of said at least one object.

2. The method of claim 1 and further comprising receiving information related to access rights of a user making the request; and wherein modifying the request comprises modifying the request if the user has access rights; and wherein executing the request comprises executing the modified request if the user has access rights.

3. The method of claim 2 wherein merging the request with the filtering criteria includes forming the modified request as a single executable statement.

4. The method of claim 1 wherein modifying the request comprises merging the request with filtering criteria to form a single executable statement, the filtering criteria being a function of the input and having therein said at least one restriction, the filtering criteria being of the same form as the request.

5. The method of claim 4 wherein merging the request comprises adding the filtering criteria to the request to form the modified request.

6. The method of claim 5 wherein merging the request includes copying the filtering criteria into the request to form the modified request on a token by token basis, wherein a token comprises an operator or an operand of the filtering criteria.

7. The method of claim 6 wherein each type of object in the request includes one or more request aliases and wherein each type in the filtering criteria includes one or more filtering aliases and wherein merging the request includes creating a unique filter alias for each type in the filtering criteria that is of a different type than the identified types in the request.

8. The method of claim 7 wherein each type and corresponding request alias of the request are in a list, and wherein merging the request includes adding each unique filter alias and corresponding type to the list.

9. The method of claim 8 wherein the filtering criteria includes a property reference in an expression to specify at least one object, and wherein merging the request includes copying the filtering criteria into the request to form the modified request on a token by token basis, wherein a token comprises an operator or an operand of the filtering criteria, the property reference being one operand.

10. The method of claim 9 wherein copying the filtering criteria into the request to form the modified request on a token by token basis is performed for each request alias of the identified types and comprises, for each token in the filtering criteria, if the token is a property reference whose filter alias is for a type other than the type of the request alias being processed, then the filter alias is replaced with the unique filter alias created for that type, otherwise, if the token is a property reference whose filter alias is for the type of the request alias, then the filter alias is replaced with the request alias.

11. The method of claim 4 wherein the request pertains to objects grouped in types, each type having associated properties and wherein the data of the objects is stored in a relational database having tables with columns for storing the data of the properties, and wherein modifying the request includes identifying types of objects in the request, and wherein merging the request with filtering criteria comprises merging the request with filtering criteria as a function of each of the identified types of objects in the request.

12. The method of claim 8 wherein the filtering criteria includes a property reference in an expression to join objects to other objects, and wherein merging the request includes copying the filtering criteria into the request to form the modified request on a token by token basis, wherein a token comprises an operator or an operand of the filtering criteria, the property reference being one operand.

13. The method of claim 12 wherein copying the filtering criteria into the request to form the modified request on a token by token basis is performed for each request alias of the identified types and comprises, for each token in the filtering criteria, if the token is a property reference whose filter alias is for a type other than the type of the request alias being processed, then the filter alias is replaced with the unique filter alias created for that type, otherwise, if the token is a property reference whose filter alias is for the type of the request alias, then the filter alias is replaced with the request alias.